Pterosaurs were the flying reptiles of the dinosaur era. With wingspans of up to 13 metres they are the largest animals ever to have flown. Dave Martill and his colleagues are revealing just how these incredible creatures got so big and yet were still able to fly.

'Pterosaurs are the closest group of reptiles to dinosaurs', explains Dave. 'These creatures are often referred to as pterodactyls but pterodactyls are only one subset of the pterosaurs the short-tailed ones. The first specimen, described in 1784, was named Pterodactylus and so the name became popular'.

Typically pterosaurs had an elongated beak and long, slender membranous wings. Many had large ferocious teeth and elaborate head crests. Some even had hair covering their neck and body. Fossil footprints show that short-tailed

pterosaurs walked on all fours, but a lack of fossil footprints of the long-tailed, so- called rhamphorhynchoids, suggests that they climbed trees or rocks to launch into flight. This behaviour fits the theory that pterosaurs evolved from tree-climbing creatures that had skin flaps for gliding much like the flying squirrels and gliding lizards that exist today. However, intermediary fossils between pterosaurs and their ancestors have yet to be found, so their evolutionary path is still unclear.

The techniques used to reveal the features and lifestyles of the pterosaurs range from the brute force of 'hammer on rock' during fossil hunting to the use of sophisticated microscopy to examine bone structure. Use of petrological and scanning electron microscopes have revealed a bone structure of multiple overlapping layers. This combination of lightness with strength is key to flight at large sizes.